1. Field of the Invention
This invention relates to devices used for eye surgery and, more particularly, to a device for assisting in the insertion of a tool or like instrument into the eye while maintaining the pressure of the eye at a safe level.
2. Description of the Prior Art
The eye is a relatively delicate and easily damaged part of the body. Therefore, eye surgery must be undertaken with great care and the instruments used during eye surgery to repair the eye must not themselves cause further eye damage.
In general, prior art surgical procedures provide for introducing the surgical tool itself directly into an incision in the eye. Sometimes a silicon sheath surrounds the tool but this sheath moves with the tool and does not insulate the eye wall from the tool. Since the instrument is introduced directly into the eye, the instrument is prone to rub against immediately adjacent eye tissue. Such rubbing against a localized area of the eye can cause eye trauma.
Further, such devices suffer from several other disadvantages. The incision, once made, is sometimes very difficult to locate. Thus, much probing is required before the tool can be introduced into the eye. Such probing can also cause eye trauma. Also, with such a technique it is difficult to assure an adequate supply of irrigation fluid to the eye to maintain safe interocular pressure. While there have been attempts to incorporate eye irrigation systems into the surgical instrument itself, this approach suffers several important disadvantages. For example, this approach does not provide adequate interocular pressure level control. Additionally, such an approach adds to the overall dimensions of the instrument and this increase in bulk is clearly not desirable when working with the eye. Also, with this approach, nothing prevents the leakage of interocular fluid from between the incision and the instrument. Such leakage can become more pronounced as the tool is manipulated, since tool manipulation can spread apart the tissue surrounding the incision.
An example of a prior art eye surgical instrument which provides irrigation can be found in U.S. Pat. No. 2,480,737. Other prior art surgical devices provide for a sleeve that can be inserted into an incision in the eye and sutured in place. Such devices are found, for example, in U.S. Pat. Nos. 3,528,425; 3,659,607; 3,732,858. However, among other disadvantages, such devices do not provide fluid irrigation for maintaining safe interocular pressure.